/*
 * Copyright (c) 2017 Cesanta Software Limited
 * All rights reserved
 */

#include "mjs_core.h"
#include "mjs_internal.h"
#include "mjs_primitive.h"

mjs_val_t mjs_mk_null(void) {
  return MJS_NULL;
}

int mjs_is_null(mjs_val_t v) {
  return v == MJS_NULL;
}

mjs_val_t mjs_mk_undefined(void) {
  return MJS_UNDEFINED;
}

int mjs_is_undefined(mjs_val_t v) {
  return v == MJS_UNDEFINED;
}

mjs_val_t mjs_mk_number(struct mjs *mjs, double v) {
  mjs_val_t res;
  (void) mjs;
  /* not every NaN is a JS NaN */
  if (isnan(v)) {
    res = MJS_TAG_NAN;
  } else {
    union {
      double d;
      mjs_val_t r;
    } u;
    u.d = v;
    res = u.r;
  }
  return res;
}

static double get_double(mjs_val_t v) {
  union {
    double d;
    mjs_val_t v;
  } u;
  u.v = v;
  /* Due to NaN packing, any non-numeric value is already a valid NaN value */
  return u.d;
}

double mjs_get_double(struct mjs *mjs, mjs_val_t v) {
  (void) mjs;
  return get_double(v);
}

int mjs_get_int(struct mjs *mjs, mjs_val_t v) {
  (void) mjs;
  /*
   * NOTE(dfrank): without double cast, all numbers >= 0x80000000 are always
   * converted to exactly 0x80000000.
   */
  return (int) (unsigned int) get_double(v);
}

int32_t mjs_get_int32(struct mjs *mjs, mjs_val_t v) {
  (void) mjs;
  return (int32_t) get_double(v);
}

int mjs_is_number(mjs_val_t v) {
  return v == MJS_TAG_NAN || !isnan(get_double(v));
}

mjs_val_t mjs_mk_boolean(struct mjs *mjs, int v) {
  (void) mjs;
  return (v ? 1 : 0) | MJS_TAG_BOOLEAN;
}

int mjs_get_bool(struct mjs *mjs, mjs_val_t v) {
  (void) mjs;
  if (mjs_is_boolean(v)) {
    return v & 1;
  } else {
    return 0;
  }
}

int mjs_is_boolean(mjs_val_t v) {
  return (v & MJS_TAG_MASK) == MJS_TAG_BOOLEAN;
}

#define MJS_IS_POINTER_LEGIT(n) \
  (((n) &MJS_TAG_MASK) == 0 || ((n) &MJS_TAG_MASK) == (~0 & MJS_TAG_MASK))

MJS_PRIVATE mjs_val_t mjs_pointer_to_value(struct mjs *mjs, void *p) {
  uint64_t n = ((uint64_t)(uintptr_t) p);

  if (!MJS_IS_POINTER_LEGIT(n)) {
    mjs_prepend_errorf(mjs, MJS_TYPE_ERROR, "invalid pointer value: %p", p);
  }
  return n & ~MJS_TAG_MASK;
}

MJS_PRIVATE mjs_val_t mjs_legit_pointer_to_value(void *p) {
  uint64_t n = ((uint64_t)(uintptr_t) p);

  assert(MJS_IS_POINTER_LEGIT(n));
  return n & ~MJS_TAG_MASK;
}

MJS_PRIVATE void *get_ptr(mjs_val_t v) {
  return (void *) (uintptr_t)(v & 0xFFFFFFFFFFFFUL);
}

void *mjs_get_ptr(struct mjs *mjs, mjs_val_t v) {
  (void) mjs;
  if (!mjs_is_foreign(v)) {
    return NULL;
  }
  return get_ptr(v);
}

mjs_val_t mjs_mk_foreign(struct mjs *mjs, void *p) {
  (void) mjs;
  return mjs_pointer_to_value(mjs, p) | MJS_TAG_FOREIGN;
}

mjs_val_t mjs_mk_foreign_func(struct mjs *mjs, mjs_func_ptr_t fn) {
  union {
    mjs_func_ptr_t fn;
    void *p;
  } u;
  u.fn = fn;
  (void) mjs;
  return mjs_pointer_to_value(mjs, u.p) | MJS_TAG_FOREIGN;
}

int mjs_is_foreign(mjs_val_t v) {
  return (v & MJS_TAG_MASK) == MJS_TAG_FOREIGN;
}

mjs_val_t mjs_mk_function(struct mjs *mjs, size_t off) {
  (void) mjs;
  return (mjs_val_t) off | MJS_TAG_FUNCTION;
}

int mjs_is_function(mjs_val_t v) {
  return (v & MJS_TAG_MASK) == MJS_TAG_FUNCTION;
}

MJS_PRIVATE void mjs_op_isnan(struct mjs *mjs) {
  mjs_val_t ret = MJS_UNDEFINED;
  mjs_val_t val = mjs_arg(mjs, 0);

  ret = mjs_mk_boolean(mjs, val == MJS_TAG_NAN);

  mjs_return(mjs, ret);
}
